Rumen-stable pellets

ABSTRACT

Pellets adapted to be orally administered to ruminants are disclosed. The pellets have a core comprising a nutrient and/or medicament, and a coating which protects the core in the environment of the rumen is also provided to allow utilization of the core in the abomasum and/or intestine. The coating comprises a polymeric matrix which is resistant to the mildly acidic environment of the rumen, a hydrophobic substance, a flake material, and reactive acid dispersed throughout the continuous matrix. The core may contain a neutralizer if desired. The continuity of the polymeric matrix is destroyed in the more acidic environment of the abomasum.

This invention relates in general to pellets adapted to be orallyadministered to ruminants and which are beneficial to ruminants afterpassing the rumen and reaching the abomasum and/or intestines. Moreparticularly, this invention relates to pellets having, in terms ofstructure, a core material such as a nutrient or medicament, and animperforate coating over the core material which protects the core inthe environment of the rumen, but which loses continuity under the moreacidic conditions of the abomasum to render the core material availablefor utilization by the animal.

In ruminants, ingested feed first passes into the rumen, where it ispre-digested or degraded by fermentation. During this period offermentation the ingested feed may be regurgitated to the mouth via thereticulum where it is salivated and ruminated. After a period offermentation regulated by natural processes and variable depending onthe animal and the feedstuff, adsorption of digested nutrients startsand continues in the subsequent sections of the digestive tract by theruminant animal. This process is described in detail by D. C. Church,"Digestive Physiology and Nutrition of Ruminants", Vol. 1, O.S.U. BookStores, Inc., of Corvallis, Ore.

The rumen, the largest of the four stomach compartments of ruminants,serves as an important location for metabolic breakdown of ingestedfoodstuffs through the action of microorganisms which are presenttherein. Ingested food is typically retained in the rumen for from about6 to 30 hours or longer in some instances, during which time it issubject to metabolic breakdown by the rumen microorganisms. Muchingested protein material is broken down in the rumen to solublepeptides and amino acids and utilized by the rumen microorganisms. Whenthe rumen contents pass into the abomasum and intestine, the microbialmass is digested, thus providing protein to the ruminant. Thus, thenatural nutritional balance of the ruminant animal is primarily afunction of the microbial composition and population.

In preparing nutrients and medicaments intended for administration toruminants, it is important to protect the active ingredients against theenvironmental conditions of the rumen, i.e., microbial degradation andthe effects of a pH of about 5.5, so the active substance will be saveduntil it reaches the particular location where adsorption takes place.It is well known that the rate of meat, wool and/or milk production canbe increased if sources of growth limiting essential amino acids, and/ormedicaments, are protected from alteration by microorganisms residing inthe rumen and become available for direct absorption by the animal laterin the gastrointestinal tract.

Materials which protect the core against degradation by the rumencontents should be resistant to attack by the rumen fluid which containsenzymes or microorganisms but must make the active ingredient availablerapidly in the more acidic fluid of the abomasum at a pH within thenormal physiological range of about 2 to about 3.5. To more easily coator encapsulate active ingredients in protective materials, theprotective materials should be soluble in certain organic solvents forcoating purposes.

Because proteins are subject to breakdown in the rumen, it has beensuggested that protein-containing nutrients fed to ruminants be treatedso as to permit passage without microbial breakdown through the rumen tothe abomasum. Suggested procedures have included coating the proteinmaterial, for example, with fats and vegetable oils; heat treating ofthe protein material; reacting the protein material with variouscompounds such as formaldehyde, acetylenic esters, polymerizedunsaturated carboxylic acid or anhydrides and phosphonitrilic halides,etc.

It is well known that all proteins found in animal and plant life arechemical compounds containing different combinations of over 20 aminoacids, the number and arrangement of such acids being fixed in anyparticular protein. Twelve of these amino acids can be synthesized innutritionally adequate amounts from other substances by biochemicalprocesses normally present in most animals, but the remaining 10essential amino acids are not synthesized in sufficient quantities andmust be ingested by the animal. Since the proportions of the constituentamino acids in a particular protein cannot be varied, the essentialamino acid least in supply limits the amount of that protein which canbe produced by the animal. Consequently, for any given diet, there willbe a particular essential amino acid which limits the production ofprotein incorporating that essential amino acid unless, of course, twoor more such amino acids are equally limiting.

The appreciation of the above principles leads to the formulation ofdiets for nonruminant animals which provide the optimum proportion ofamino acids and have enabled significant increases in protein productionto be achieved. In the ruminant, dietary proteins and amino acids are,to a variable extent, broken down to ammonia and various organiccompounds by microbial fermentation in the first two compartments of thestomach (the rumen and reticulum). The bacteria and protozoa in theseorgans utilize these metabolites for their own growth and multiplicationand the microbial protein so formed passes on to the abomasum, thecompartment of the stomach corresponding to the stomach of nonruminants,where it is partially digested. The process is completed in the smallintestine and the amino acids are absorbed.

It is likewise well-known that medicaments are more effective when theyare protected from the environment of the rumen. See, for example, U.S.Pat. Nos. 3,041,243 and 3,697,640.

In accordance with the present invention, a polymeric coating having ahydrophobic substance, a flake material, and reactive acid dispersedtherein, which is resistant to environmental conditions of the rumen butreleases the core material under the environmental conditions of theabomasum, provides a very desirable utilization efficiency by ruminants.The core material may also contain a neutralizer to provide a pH aboveabout 5.5.

Difficulty has been encountered with known coated pellets in attainingthe necessary characteristics of protection and release at efficienciesrequired in commercial applications. When pellets are coated inaccordance with the present invention, a surprisingly high percentage ofthe coated pellets are found (1) to be protected in the environment ofthe rumen for the required time, and (2) to release the core material inthe environment of the abomasum within the required time. It wasunexpected that the coating described herein would demonstate such anincreased efficiency. For example, at least 60%, and normally at least75% and frequently higher percentages of the pellet core material willbe protected by the coating for the required time in the mildly acidicenvironment of the rumen and be released by the coating within therequired time in the more acidic environment of the abomasum. Thisincreased efficiency may be due to the acid sensitivity characteristicsof the coating, the resistance to abrasion in handling and/or theresistance to sticking under relatively high heat and humidityconditions which may damage the coating.

The coating material has the ability to withstand environmentalconditions of the rumen, and the ability to expose the core material ofthe pellet in the environment of the abomasum. Thus, the coatingmaterial is resistant to pH conditions of about 5.5 for at least about24 hours. The coating material releases the core material upon exposureto abomasum environmental conditions having a pH of about 3.5 after atime of about 10 minutes to about 6 hours. The exposure of the core mayoccur by the coating becoming permeable to the fluids therein or bydissolving or disintegrating. Another requirement for the coatingmaterial is to have the ability to withstand storage conditions ofrelatively high heat and/or humidity without a significant amount ofblocking.

Core materials having an adjusted pH of greater than about 5.5 and awater solubility of about 10 to about 70 grams per hundred grams waterat 25° C. are most useful in this invention. Thus, any core materialwhich is beneficial to the ruminant such as a nutrient or medicamenthaving characteristics within these parameters may be used. Preferredcore materials include amino acids, proteins, various other nutrients,as well as antibiotics and other medicaments.

BACKGROUND

U.S. Pat. No. 3,619,200 relates to chemically modifying pellets and/orusing a surface coating therefor. Proteinaceous feed is protected frombreakdown within the rumen by the modification of protein itself, by theapplication of a protective coating to the feedstuff, or by combinationof both. Various polymers are disclosed in this patent includingcopolymers of vinylpyridine and styrene. Canadian Pat. No. 911,649discloses treatment of proeteinaceous materials with substances whichare capable of reacting with proteins to form a polymeric proteinaceouscomplex on the surface of the material or by treating the proteinaceousmaterial with a polymer or copolymer of a basic vinyl or acrylicmonomer. This patent also discloses the use of copolymers andterpolymers derived from essentially a basic substituted acrylate ormethacrylate monomer and at least one ethylenically unsaturated compoundas rumen stable coatings. U.S. Pat. No. 3,880,990 and British Pat. No.1,346,739 relate to an orally administratable ruminant compositionwherein a medicinal substance is encapsulated or embedded in a normallysolid, physiologically acceptable basic polymer. The compositions areproduced by dispersing a medicinal substance in a first solvent andadding thereto a second solvent which is miscible with the first solventbut in which the polymer and medicinal substance are substantiallyinsoluble. There is no suggestion of modifying the polymer by the use ofadditives. U.S. Pat. No. 3,041,243 relates to coatings for oralmedicaments. These coatings are water-insoluble but acid-solublefilm-forming polymers. An example mentioned in this patent is2-methyl-5-vinyl pyridine copolymerized with vinyl acetateacrylonitrile, methyl acrylate or styrene.

U.S. Pat. No. 3,697,640 relates to materials such as medicaments andnutrients for ruminants which are coated with nitrogen-containingcellulosic materials such as, for example, cellulose propionatemorpholino butyrate. This patent, however, fails to suggest the use ofany additives in the nitrogen-containing cellulosic material, and U.S.Pat. No. 3,988,480 relates to a proteinaceous feedstuff for ruminantswhich has been treated with acetic acid to render it rumen stable.

U.S. Pat. No. 3,383,283 relates to coating pharmaceutical pellets with aplurality of charges of fatty acid as a melt or in solution. The fattyacid may then be dusted with a fine inert powder such as talc. There isno suggestion of using a continuous matrix polymer.

U.S. Pat. No. 3,275,518 relates to a tablet coating compositioncomprising a film-forming resin or plastic and a hard water-soluble orwater-dispersible substance. Stearic acid is mentioned as an optionalwater-insoluble wax which may be included as an additive. Additionalmaterials such as dyes, pigments, water-insoluble waxes, plasticizingagents, etc., may also be added to the coating. However, thefilm-forming resin or plastic according to this patent is selected fromthe group consisting of poly(methylstyrene), methylstyrene-acrylonitrilecopolymers, poly(vinylchloride), poly(vinyl butyral), pentaerythritol oralkyd esters of rosin or modified rosin and terpene derived alkydresins. There is no suggestion of the polymers according to applicants'invention. In fact, the plastic or resin is described aswater-permeable, and the coating apparently is not designed forruminants.

U.S. Pat. No. 3,623,997 relates to a method of sealing polymericmaterial walls of minute capsules by treating the capsules with a waxymaterial. The wax is introduced in a solvent which is subsequently driedand the wax is left as a residue in the walls. The capsule walls shrinkand lose solvent and then entrap the wax tightly as a sealing material.There is no indication, however, that the polymer coating is designed tofunction for ruminants, and the wax is used as a sealing material.Applicant's hydrophobic substance is dispersed in the polymer.

U.S. Pat. No. 3,073,748 relates to tablets coated with a solution of anamphoteric film-forming polymer. The polymer is described as oneselected from the group consisting of copolymers of (a) vinylpyridineswith (b) a lower aliphatic α,β-unsaturated monocarboxylic acid of 3 to 4carbon atoms and copolymers of (a), (b) and a neutral comonomer selectedfrom the group consisting of methyl acrylate, acrylonitrile, vinylacetate, methyl methacrylate and styrene. There is no suggestion ofusing a dispersed additive.

British Pat. No. 1,217,365 and Canadian counterpart No. 851,128 relateto a particulate feed additive composition for ruminants wherein eachparticle comprises one or more amino acids totally encased in acontinuous film of protective material which is transportable throughthe rumen without substantial degradation therein but which releases theactive substance posterior to the omasum when the particles have adensity within the range of 0.8 to 2.0 and diameters in the range of 200to 2,000 microns. Suggested as protective materials are fatty acidtriglycerides such as hydrogenated vegetable and animal fats, waxes suchas rice-brand wax, and resin wax blends which are emulsified and/ordissolved in the intestinal tract.

PELLETS

The pellets according to this invention are adapted for oraladministration to a ruminant. The pellets are of a suitable size, suchas between about 0.05 in. and 0.75 in. in diameter. Also, the pelletsmust be of suitable density, i.e., a specific gravity of between about 1and 1.4, have acceptable odor, taste, feel, etc. The pellets include acore and a continuous, film or coating completely encapsulating thecore. The shape is usually not critical, except the pellets are commonlyspherical for ease in coating.

CORE MATERIAL

The core is of a material beneficial to the ruminant upon passing therumen and reaching the abomasum and/or intestine. Normally, the core isa solid material which has been formed into particles, such as bypelletizing. The cores may then be rounded if desired, by conventionalmeans, such as by tumbling. The core should have sufficient body orconsistency to remain intact during handling, particularly during thecoating operation. Suitable core materials include various medicamentsand nutrients such as, for example, antibiotics, relaxants, drugs,anti-parasites, amino acids, proteins, sugars, carbohydrates, etc. Thecore may also contain inert filler material such as clay.

Some amino acids suitable for use as a core material, their pH andsolubility are as follows:

    ______________________________________                                        Amino Acids Solubility and pH of Saturated Solutions                                           Solubility g./100 g. water                                                    at 25° C.                                                                        pH                                                 ______________________________________                                        DL - Alanine       16.7        6.2                                            L - Asparagine     3.1         4.7                                            L - Arginine       21.6        11.8                                           L(-) - Cysteine    0.01        3.7                                            DL - Methionine    4.0         5.7                                            L(-) - Lencine     2.0         4.8                                            L(-) - Tyrosine    0.05        7.3                                            DL - Phenylalanine 3.0         5.6                                            ______________________________________                                    

Other suitable active core materials include glucose, bacitracin,thyrotropin releasing factor and inositol. Proteins from various sourcesare valuable for practice of the invention. Generally, proteins arepolymers derived from various combinations of amino acids. Proteins areamphoteric substances which are soluble or suspendable in aqueous mediaeither more acidic or more basic than the particular protein beingconsidered.

The core material may be made ready for coating by the following method.The nutrient, medicament, or the like, and core neutralizer, if used,are mixed with water, binders, a basic substance for adjusting the corepH, and sometimes inert inorganic substances added to adjust thespecific gravity of the pellet and the resulting plastic dough-like massis extruded or rolled to obtain suitable size particles. Adhesivebinders are added to strengthen the pellet and can be nontoxic vegetablegums, starches, cellulose derivatives, animal gums and other similarsubstances well-known in the art of food thickening and tablet making.Inorganic additives used to adjust the specific gravity of the pelletinclude such substances as insoluble, nontoxic pigment-like materialssuch as metal sulfates, oxides and carbonates having a relatively highdensity. The final desirable range of specific gravity for the rumenprotected pellets is from 1.0 to 1.4. After creating suitable sizepellets by extrusion, rolling or other suitable means, the pellets aredried to remove the water. The pellets are then coated by contactingthem with a solution of the protective coating material in a suitablesolvent or mixture of solvents as hereinafter described. Typicalsolvents of value include lower alcohols, ketones, esters, hydrocarbons,and chlorinated hydrocarbons.

CORE NEUTRALIZATION

Core materials may be raised in pH to a predetermined degree by mixing abasic neutralization substance therewith or by coating the core with abasic neutralization substance. The acidity is modified by addingnontoxic, insoluble, basic substances such as alkaline earth oxides,hydroxides, or carbonates, to the core material before the pelletforming step. Basic compounds of aluminum such as the various forms ofhydrated alumina, aluminum hydroxide, and dibasic aluminum salts oforganic acids, having less than 6 carbon atoms, such as dibasic aluminumacetate may also be used. These basic substances are added to thepellets by mixing the core material, basic substance, and binders asdescribed above before adding water. The amount used depends on both thesolubility and relative acidic nature of the proteinaceous substance, onthe coating composition used to obtain rumen protection and on thethickness of the coating applied. The amount of basic substance used isthat quantity which will theoretically neutralize or raise the pH atleast to 5.68, preferably to about 7.

The core material may be neutralized by the following method. Nontoxic,insoluble basic substances such as oxides, hydroxides, carbonates, andbasic salts of magnesium, calcium, and aluminum are blended withfinely-divided nutrient and/or therapeutic substances at the time theseare prepared for pelletizing. The amount of basic substance used dependson several interacting factors related to the relative acidity and/orsolubility of the pellet, the time required for rumen protection, andthe time required for release in the abomasum. Normally, the weight ofbasic substance will be within the range of 1-20% of the total weight ofthe core. In addition to the nutrient or therapeutic substance and thebasic substance, the pellets may contain binders, density modifiers, andother minor ingredients required for special properties, as is commonpractice in the art of tablet making. In this practice of the invention,the various powdered ingredients are first dry blended to obtain a moreor less homogeneous mixture, then water is added to obtain a plasticdough-like mass. The dough is then pelletized by extrusion, extrusionand tumbling, or by any method known to the art of pelletizing ortabletmaking. The water is removed by drying at ambient conditions, inheated ovens or fluidized beds. The dry pellets are then ready forsubsequent coating operations performed by any method such as pancoating, fluidized bed coating, or spray coating or combinationsthereof.

Another method of core neutralization is based on the concept that,whereas the coating is permeable to water and acidic water bornemolecules, not all of the pellet interior is required to be neutralized.In this method of practicing the invention, the nontoxic inorganic basicsubstances are deposited on the surface of the core material prior toapplication of the coating. In practice, the preformed pellets areplaced in a fluidized bed or other coating apparatus and a dispersion ofan oxide, hydroxide, carbonate, or basic salt of magnesium, calcium, oraluminum in water or an organic liquid is sprayed on the pellet. Thedispersion of basic substance preferably contains a binder and may alsocontain a protective colloidal substance wherein the ratio of binderplus protective colloidal substance to basic substance is less thanabout 1:3. The amount of basic substance coated onto the pellet isnormally from about 1 to about 20% of the weight of the core material.The binder and protective colloidal substance can be the same substanceor different and are preferably soluble or dispersible in water and inthe organic liquid used to suspend the basic substance. Such bindermaterials as relatively low molecular weight cellulose derivatives,synthetic polymers, and natural gums known to the art of tablet makingare suitable for the practice of the invention. The organic liquid canbe any having suitable solvent power and boiling in the range of from40°-140° C.

COATING

The coating material is capable of forming a continuous film around thecore by the evaporation of solvent from the coating material. It has theability to withstand environmental conditions of the rumen, and theability to expose the core material of the pellet in the environment ofthe abomasum. Thus, the coating material should be resistant to pHconditions of greater than about 5 for from about 6 to about 30 hours.The coating material should release the core material after exposure toabomasum environmental conditions having a pH of about 2 to about 3.3.Release should occur within the residence time in the abomasum or laterin the intestinal tract but at least within a time period of 6 hoursafter contacting pH 3.5 or less. The exposure of the core may occur bythe coating becoming permeable to the contents of the rumen, such as bydissolving, disintegrating, or extensive swelling. The coating materialis physiologically acceptable, i.e., the coating material should notinterfere with the ruminants' healthy or normal body functioning.

Another requirement for the coating material is its ability to withstandabrasion in handling and storage conditions of relatively high heatand/or humidity without a significant amount of blocking or sticking. Itshould have a sticking temperature of greater than about 50° C. Stickingtemperature is defined as the temperature at which an applied force of0.25 Kg/cm² for 24 hours causes the coating of pellets to adhere to thecoating of adjacent pellets strongly enough to cause rupture of thecoating when the pellets are forceably separated. Also, the coatingmaterial is preferably soluble or dispersable in organic solvents havingboiling points of between about 40° C. and 140° C. to permitconventional coating processes such as spray coating to be used.Particularly suitable solvents include methylene chloride, chloroform,ethanol, methanol, ethyl acetate, acetone, toluene, isopropanol ormixtures of these.

The coating or film forming material according to this inventionincludes a mixture or blend of at least one polymeric substance, atleast one hydrophobic substance, and at least one flake material.Generally, the more acidic and more soluble core materials requiregreater ratios of hydrophobic substance and flake material to polymericsubstance, while more basic and less soluble core materials requirelesser ratios of hydrophobic substance and flake material to polymericsubstance within this range. The hydrophobic substance and flakematerial are normally dispersed in the polymeric matrix. The hydrophobicsubstance is normally present in amounts of between about 2 and about40% and the flake material is normally present in amounts between about10 and 200%, based on the weight of the polymeric material. The coatingnormally accounts for from 5 to about 50% by weight of the pellet.

POLYMER

The polymeric substances which are useful in the coatings of thisinvention include those which, in combination with the hydrophobicsubstance described hereinafter, are physiologically acceptable andresistant to a pH of greater than about 5 but capable of releasing thecore of the pellets at a pH of less than about 3.5, at the normal bodytemperature of ruminants (about 37° C.).

The polymeric substances are macromolecules of sufficient molecularweight to have film-forming properties when the polymer is depositedfrom a solution and after removal of a solvent, dispersing medium or oncooling from a melt. Typical molecular weights will be in the range offrom about 5,000 to about 300,000.

Polymeric substances having the characteristics defined herein includecertain modified natural polymers, homo- and interpolymers, containingat least one basic amino group in which the nitrogen content is from 3to 14% by weight of the total molecular weight of the polymericmaterial. The polymeric material is at least one polymer, copolymer, orblend of polymers selected from the group consisting of cellulosepropionate morpholinobutyrate, poly(vinylpyridine), and polymericderivatives of vinylpyridine specifically, polymer comprising2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine and2-ethyl-5-vinylpyridine. Especially preferred is a copolymer of about75-85% by weight 2-methyl-5-vinylpyridine and about 15-25% by weightstyrene, and in particular about 80% by weight 2-methyl-5-vinylpyridineand about 20% by weight styrene.

Preferred also are copolymers of vinylpyridine and acrylonitrile, and inparticular, the copolymer of about 55-65% by weight2-methyl-5-vinylpyridine and about 35-45% by weight acrylonitrile. Thesecopolymers are commercially available or may be produced by conventionaltechniques well known in the art. Conventional additives such asplasticizers may be used in the polymer.

HYDROPHOBIC SUBSTANCE

Useful hydrophobic substances which are physiologically acceptable arecommercially available. The polymer and hydrophobic substance shouldhave a degree of compatability to permit the film to remain intact inthe rumen environment, but to permit permeation of the abomasal fluid tothe core while the pellet is in the abomasum.

Suitable hydrophobic substances include fatty acids, dimer acids, trimeracids, and aluminum salts of fatty acids. The useful hydrophobicsubstances are fatty acids having from 12 to 32 carbon atoms such as,for example, oleic acid and stearic acid. Aluminum salts of such acids,for example, aluminum oleate, aluminum stearate, aluminum dimerate, arealso useful. Also, the hydrophobic material may be one or morepolycarboxylic acids having a ratio of from 10 to 22 carbon atoms percarboxyl group and a molecular weight of from about 400 to about 1000.Blends of these acids and/or salts are also useful.

Inert filler materials such as clay, bentonite, limestone, etc., mayalso be used in suitable amounts.

FUNCTIONAL FLAKE MATERIAL

In accordance with this invention, a physiologically acceptable flakematerial is dispersed throughout the polymeric matrix. The flakematerial is substantially inert with respect to the environment of therumen.

Suitable inert flake materials include metal flake, mineral flake,crosslinked organic polymer, etc. Especially suitable are aluminumflake, talc, graphite, and ground mica.

REACTIVE ACIDS

In accordance with this invention, one or more fatty acids are used withthe inert flake material to form a coating resistant to the environmentof the rumen, but which will permit permeation of the abomasum contentsinto the core material. These acids react with the flake material tojoin adjacent flakes and bind the flakes together to form a strongbarrier against the acidic environment of the rumen.

Acids which may be used include fatty acids having 12 to 32 carbonatoms, and polyfunctional carboxylic acids having a ratio of from 10 to22 carbon atoms per carboxyl group and a molecular weight greater than300.

Especially preferred are dimer acid, oleic acid, stearic acid, andpalmitic acid.

Such acids may conveniently be used in amounts of 5 to 40 percent byweight, based on the weight of the polymer.

APPLICATION OF COATING

In the practice of this invention, the polymeric material mayconveniently be dissolved in a suitable organic solvent which would bephysiologically acceptable in the event there are residues uponevaporation of the solvent, as hereinbefore described. The hydrophobicsubstance is blended in the solution, wherein the polymeric substance isa continuous matrix and the additives are dispersed therein. The coatingsolution may be applied by various well known means such as, forexample, brushing, dipping, spraying, fluidized bed, etc.

A preferred apparatus and process for coating the cores will now bedescribed.

In the drawings:

FIG. 1 is an elevation view in cross-section illustrating the apparatusand showing the gas flows and particle flow path from the annular bed toand through the truncated hollow cone and in return to the annular bed;

FIG. 2 is a partial elevation view in cross-section of a modifiedapparatus and illustrating the addition of an annular airfoil andshowing the flow of gases relative to the aerodynamic structure andannular airfoil;

FIG. 3 is a partial elevation view in cross-section of another modifiedapparatus similar in all other respects to the modification shown inFIG. 2 except that the cross-section of the apparatus below the coatingchamber is of the same diameter as that of the coating chamber;

FIG. 4 is a partial elevation view in cross-section of the upper portionof the apparatus of the invention for illustrating one possible mannerof collecting the finally coated particles by use of an air porous bag;and

FIG. 5 is a graphic illustration of the height, thickness and angularrelationships of the annular airfoil with respect to the aerodynamicstructure, and the height above (h_(a)) and height below (h_(b))relationships of the aerodynamic structure to the greatestcross-sectional diameter of the aerodynamic structure.

The apparatus employs a truncated hollow cone in which the slope orpitch of the walls is such that the particles are accelerated at anincreasing rate and not just at a rate so as to maintain the gasvelocity at any given point in the cone at a level greater than thatnecessary to move the particles in a continuous upward direction. Theslope or pitch of the walls would therefore appear to be more pronouncedthan the slope or pitch of the cone embodiment disclosed in the Larsonet al patent. The significance of the slope or pitch of the truncatedhollow cone of the invention is that when a particle first enters thecone at one rate of speed, it is then accelerated to a different rate ofspeed and continues to be accelerated to still different rates of speedas it moves upwardly through the cone. In this manner a separation isbrought about between the particles so that after they are coated theymay become sufficiently dry before coming into contact with otherparticles and thereby avoid undesirable clumping or agglomeratingtogether. The pitch of slope is such as to cause a compression of thegas molecules and thereby cause the acceleration at an increasing rate.

In reference to FIG. 1, the coating apparatus is designated in generalat 10 and includes a vertically disposed first hollow column 12 ofregular shape. By "regular shape" is meant that it may be cylindrical,octagonal, hexagonal or of other configurations, so long as the hollowcolumn is generally symmetrical with respect to its central axis. Thehollow column contains therewithin the practicle storage, coating,drying and deceleration zones, which will be described herein.

A truncated hollow cone 14, which may also be a tapered octagon or othertapered polygonal configuration, in other words, generally cone-shapedconfigurations, serving as an enclosure in which the upwardly flowinggases are received, compressed and accelerated, is centrally disposedwithin the first hollow column, has a uniformly decreasing cross-sectionin the upward direction and is of predetermined height dependent uponthe size and weight of the particle to be treated. Within the truncatedhollow cone in ascending order are the coating and drying zones. Thecone serves also to separate the coating and drying zones from thedeceleration zone, which lies in the region above the upper end of thecone, and from the storage zone, which lies therebetween the cone andthe interior wall surface of the first hollow column.

The first hollow column 12 is provided at its lower end with an inwardlytapered base 16. The lower end of the truncated hollow cone is spacedradially inwardly from the inwardly tapered base.

A second vertically disposed hollow column 18 of regular shape isconnected to the inwardly tapered base of the lower end of the firsthollow column, the wall surface of the inwardly tapered base forms ajuncture with the wall surface of the second hollow column.

Disposed within the second hollow column is a first plenum chamber 20into which a suitable compressed gas, such as air, may be providedthrough two or more opposed inlets 22, 24; a gas or air collimatingplate 26; a second plenum chamber 28 separated from the first plenumchamber 20 by the collimating plate 26; at least one gas shaping oraerodynamic structure 30 disposed within the second plenum chamber; anda particle support or supporting screen 32, which extends across thesecond hollow column and is located above the aerodynamic structure.

The gas or air collimating plate 26 is a perforated plate which causesthe gas or air in the first plenum chamber to pass into the secondplenum chamber in an essentially vertical and uniform flow, asillustrated by the vertical arrows.

The gas shaping or aerodynamic structure 30 in cooperation with theadjacent wall surface of the second hollow column, compresses andfocuses the upwardly moving gas or air flow so that it flows over aportion of the surface of the aerodynamic structure, upwardly throughthe particle support screen and into the entrance end of the truncatedhollow cone. The flow upwardly around the aerodynamic structureconstitutes an annular flow, which adheres to the surface of theaerodynamic structure in the nature of a Coanda flow.

A spray nozzle 34 preferably extends above the top of the aerodynamicstructure 30 through which is sprayed a suitable coating material. It ismore convenient to have the spray nozzle located at the top of thecentrally disposed aerodynamic structure. The coating material issupplied from a suitable source (not shown) through a conduit 36extending up through the aerodynamic structure, and an atomizing gas maybe supplied from a suitable source (not shown) through a conduit 38,also extending up through the aerodynamic structure, for subsequentmixing at the nozzle. The spray nozzle may also be pressure-operatedrather than gas-operated.

The upper surface of the gas shaping or areodynamic structure iscentrally disposed within and extends generally horizontally across thecross-section of the vertically disposed hollow column. In other words,it has a cross-sectional plane generally perpendicular to the verticalaxis of the vertically disposed hollow columns. The outer edge of theupper surface is equally spaced from the wall surface of the hollowcolumn and defines therebetween with the wall surface of the hollowcolumn a reduced pressure region for acceleration in velocity of theupwardly flowing gases in such manner that the upwardly flowing gasesform a boundary layer that is directed away from the wall surface of thehollow column and that adheres to the upper surface of the gas shapingor aerodynamic structure for flow across a portion thereof.

The upper surface of the aerodynamic structure may be flat (notillustrated), but is preferably curved or approximately spherical asillustrated. It may have a height (h_(a)) above the cross-sectionalplane (See FIG. 5), therefore, of from about 0% to about 150%, orpreferably from about 10% to about 150% of the greatest cross-sectionaldiameter (D) (See FIG. 5) of the aerodynamic structure.

The surface below the greatest cross-sectional diameter may also be flat(not illustrated) and may therefore have a depth or height (h_(b)) belowof from about 0% to about 200% of the greatest cross-sectional diameter(D) (See FIG. 5). Preferably, the surface below is formed in the mannerdisclosed in the drawings.

The aerodynamic structure as disclosed and as described is thus adaptedto compress and accelerate the flowing gases near the periphery of thehollow column and direct them toward the center of the hollow column atan angle from about 10° to about 45° from a direction parallel to theflowing gases from the gas or air plenums.

The truncated hollow cone defines at its lower end a large diametersomewhat smaller than the diameter of the vertically disposed firsthollow column, and has an increased diameter from about 0% to about 25%greater than that of the plane of the particle support screen. The lowerend of the truncated hollow cone is spaced a predetermined amount fromthe screen and the upper end defines a diameter of from about 20% toabout 80% of that of the lower end. The height of the cone ranges fromabout one to about six times the diameter of the lower end.

In operation, particles 40 may be suitably loaded into the coatingapparatus 10, as through a closable opening at 42, into the storage zonelying between the wall surface of the first hollow column 12 and theoutside wall surface of the truncated hollow cone 14. The particles arethus situated in an annular bed around the truncated hollow cone 14. Thesloping outer wall surface of the truncated hollow cone, the inwardlysloping tapered base 16 of the first hollow column and the screen 32serve to contain the particles in the annular bed prior to starting-upthe coating operation.

The gas or air is turned on to start the circulation of the particles orpellets from the annular bed or storage zone into the coating, dryingand deceleration zones and in return to the upper portion of the annularbed. The atomizing spray is then turned on and appropriately adjusted ina suitable manner by controls (not shown).

As previously pointed out, the Coanda flow or effect is named for thetendency of a fluid, either gaseous or liquid, to cling to a surfacethat is near an orifice from which the fluid emerges. Such "orifice" inthis instance is formed in the region therebetween the closest approachof the aerodynamic structure to the adjacent side wall surface. The gasflow emerging from the "orifice" region around the aerodynamic structureis an annular flow which clings or adheres to the surface of theaerodynamic structure. The flow, therefore, from any one selectedlocation around the "orifice" is opposed by the other flows so that itis prevented from continuing further over the upper surface of theaerodynamic structure by being forced upwardly away from the uppersurface at some point for flow into the truncated hollow cone. A partialvacuum is formed in the region just above the upper surface of theaerodynamic structure and at the lower edge of the truncated hollow coneand this aids in the compression and focusing of the rising annular flowof gases. The upward flow is consequently caused to have a conicalshape, as seen in phantom lines in FIG. 1 at 44 within the cone, and hasa centering effect on the particle impelled upwardly through the cone.

As also pointed out, an important part of the Coanda effect is thetendency of the flow or gas or liquid to entrain, or draw in, more gasor liquid from the surrounding environment. In this latter manner, theparticles are pulled from the annular bed or storage zone into theupwardly flowing gas due to the aforementioned partial vacuum or reducedpressure region that exists just above the screen adjacent the path ofupward flow as a consequence of this Coanda effect. This reducedpressure or partial vacuum is directed perpendicular to the annularairflow from the "orifice". It is a different effect, however, from thehorizontal shunting action occurring in the Wurster et al apparatusdescribed above because there the horizontal shunting would extend notonly toward the axis of the apparatus but also inefficiently toward theouter wall surface of the coating apparatus.

Once the particles are pulled into the upwardly flowing gas within thetruncated hollow cone, they are impelled upwardly in an accelerating gasor air stream. As the particles pass through the lower central region orcoating zone within the cone, they are contacted with an atomized spraycoating of material. This atomized spray emerges from the spray nozzle34 because the liquid coating substance is either forced through asingle orifice designed to convert bulk liquids into droplets, or theliquid and an atomizing air stream emerge simultaneously from jetsadjacent to each other. In either case, the fine droplets of coatingmaterial are in a flowable state, because the material is dissolved ormelted in the region immediately above the spray nozzle.

Further up the truncated hollow cone, the liquid nature of the coatingmaterial, as deposited on the pellets or particles, changes to solid byevaporative or other solidification processes. During the transitionfrom liquid to solid, the coated particles pass through a stage whenthey are sticky or tacky and would agglomerate if they contacted eachother. This contact is prevented by the slope or pitch of the walls ofthe truncated hollow cone and consequent accelerating boost of theparticles to separate them in the manner previously discussed.

The conical nature of the cone causes a compression and acceleration ofthe rising column of gases and the upward velocity or acceleration ofthe particles occurs at an increasing rate as they rise in the cone.This acceleration causes an increasing vertical separation in spacebetween the particles and therefore reduces the tendency for theparticles to contact each other until the coating has become nontacky.It is this region of the cone that is thus called the "drying zone".

When the compressed gases and entrained particles pass upwardly out ofthe upper end of the cone, they expand into the larger area of the upperportion of the first hollow column and thus decelerate to a velocity toolow to suspend the particles. This is the deceleration zone, wherefurther drying takes place, and the particles then fall by gravityaction to the annular bed where they gradually move down, also due togravity, until they are pulled into the coating zone again. Thisrecycling or recirculation continues until, based on previousexperiments, a sufficient coating has been applied.

The atomized spray is turned off, and the gas or air entraining flow maybe shut down or may be increased to drive the coated particles into theuppermost region of the first hollow column, as for collection in themanner illustrated in FIG. 4. Any other suitable manner of unloading thefinally coated particles may also be used.

A coating apparatus having the design characteristics essentially asshown in FIG. 1, and having a diameter of eight (8) inches across thelower end and four (4) inches across the upper end of the truncatedhollow cone, is charged with twenty-five (25) pounds of generallyspherical pellets of animal feed supplement. The pellets are composed of90% methionine and 10% binders. The average diameter of the sphericalpellets is about 3 millimeter. About 250 standard cubic feet per minuteof air at about 7 p.s.i.g. is admitted to the plenum chamber 20. Thisair causes a circulation of pellets through the truncated hollow cone14, and the height of the cone above the support screen 32 is adjustedto obtain a pellet flow rate such that all the pellets in the annularstorage zone move through the cone about once every minute. A coatingsolution is pumped through the spray nozzle 34 at the same time as 5SCFM of atomizing air at 40 p.s.i.g. is supplied to the nozzle. Thepumping rate is adjusted to pump one (1) pound of solution per minute.The apparatus is operated for about 45 minutes. The product is a pelletcore coated with about a 2-mil layer of the polymer.

If the gases flowing upwardly around the aerodynamic structure could beseen as a series of layers of molecules, merely for sake of discussion,it is thought that there is an insignificant flow of molecules or layeror so of molecules along the interior wall surface of the second hollowcolumn. By "insignificant" is meant that such layer or layers ofmolecules will not perform any supporting function of the particles inthe annular bed.

Moving, therefore, radially inwardly from the interior wall surface ofthe second hollow, the more significant layers of molecules are causedto bend toward the gas shaping or aerodynamic structure, the innermostadhering to the surface of that structure as they pass upwardly throughthe "orifice" region. This adherence of the molecules to the surface ofthe aerodynamic structure may be favorably compared to the "teapoteffect", which is a low-speed form of the "Coanda effect". When water ispoured slowly from a glass, it tends to stick to the side of the glassin the same way that tea sticks to the spout of a teapot. High speedfluids behave similarly and adhere to a surface of suitable shape.

As the rising molecules flow over the surface of the aerodynamicstructure after having passed the "orifice" region, previouslymentioned, at some point along the upper surface of the aerodynamicstructure the opposing character of the annular flow forces themolecules upwardly away from the upper surface as well as the adjacentmolecule layers. A partial vacuum is created above the aerodynamicstructure due to the high speed upward flow of gases, causing an inwardbending of the upwardly moving molecules.

In the apparatus herein described, the particles move down in theannular bed by gravity without any "dancing" occurring, and are drawninto the upwardly flowing gases by the partial vacuum. Thus, anyattrition that might occur is greatly minimized, and the overalloperation is much more efficient.

In reference to FIG. 2 in which a modification is disclosed, the samereference numbers will be used to identify similar elements previouslydescribed, except that they will be primed to show that it is adifferent embodiment under discussion.

FIG. 2 represents an embodiment wherein the size of the coatingapparatus 10' has been increased in order to handle larger batch loadsof particles for coating treatment. It has been found that it is morepractical to add an additional gas shaping or aerodynamic structure oran annular airfoil 50 instead of increasing the size of the aerodynamicstructure 30'. In this manner, larger amounts of upwardly flowing gas orair may be supplied undiminished or unobstructed by a larger aerodynamicstructure, and the annular airfoil serves to supplement the compressionand focusing action on the upward gas flows so that substantially allgas flows move through the truncated hollow cone 14'.

Additional or multiple gas shaping or annular airfoils (not shown) alsomay be used for still larger coating apparatus. The exact shape andplacement of the airfoils are functions of a number of variables. Themost significant of the variables are size of the apparatus, size of theparticle to be coated, density of the particle, rate of gas or air flowand the rate of recirculation of the particles through the coating zonedesired.

In a larger-scale coating apparatus, therefore, one or more annularlyshaped and placed gas shaping or aerodynamic structures or airfoils,angled or curved, may be provided concentric with and radially outwardlyof the central gas shaping or aerodynamic structure. The annularairfoils may be attached to the central aerodynamic structure or to thewalls of the coating apparatus by radial struts in such manner as toexert a minimum deflection of the upwardly flowing gases.

The annular aerodynamic structure is inwardly inclined in the upwarddirection so that its inclination lies in a plane extending about 10° toabout 45°, as measured from the axis perpendicular to the diameter ofthe coating apparatus. The inwardly inclined annular structure providesa surface on which the gas or air impinges for subsequent shaping anddirection upwardly into the truncated hollow cone.

The vertical height of the annular structure may be about 10-50% of theperpendicular cross section diameter of the coating apparatus.

In reference to FIG. 5, when the annular gas shaping structure has theconfiguration of an airfoil having at least one curved surface extendinggenerally in the direction of gas flow, the overall angle of a linedescribed from a point p₁, on the lower rim of the airfoil to a point,p₂, on the upper rim in the vertical direction, or perpendicular to aline which is tangent to the upper curved surface of the centrallydisposed aerodynamic structure, is from about 10° to about 45° inwardfacing, as measured from the axis perpendicular to the diameter of thecoating apparatus.

The cross-sectional configuration of an annular airfoil in a planedescribed from the center of the cross-sectional area of the coatingapparatus to a point, p₁, on the lower rim of the airfoil to a point,p₂, in the upper rim of the airfoil is teardrop, or similar to thecross-sectional shape of a lifting aerodynamic shape, and having thethicker cross section on the forward part with reference to thedirection facing the upwardly flowing gases. The thickest part islocated about two-fifths (2/5) to about one-half (1/2) of the height inthe vertical direction. In other words, the height (H) of the thickestpart (T), or HT is equal to about 2/5 H to about 1/2H. The thickestcross section (T) is from about one-sixth (1/6) to about two-fifths(2/5) of the height (H) of the airfoil; or T is equal to about 1/6 H toabout 2/5 H.

The size, placement and geometrical configuration of the annular gasshaping structure are such, therefore, that the upwardly flowing gasesare deflected radially inwardly at an angle from about 10° to about 45°from a direction parallel to the original gas flow.

In reference to FIG. 3, the same reference numbers will be used toidentify similar elements previously described, except that they will bedouble-primed to show that it is still another different embodimentunder discussion.

FIG. 3 represents an embodiment wherein the size of the coatingapparatus 10" has been increased to the same extent as that disclosed inthe FIG. 2 embodiment. The embodiment in FIG. 3 differs from theembodiment in FIG. 2 in that the first and second hollow columns aredisclosed as being co-extensive in cross-sectional diameter. In otherwords, the coating apparatus is disposed within a single hollow column.It could also be of smaller size so that only one gas shaping oraerodynamic structure 30" is employed as in FIG. 1, instead of a sizerequiring the annular airfoil 50".

The recycling or recirculation in this embodiment is necessarily fasterbecause the particles are not as readily restrained in the annular bedregion as they would be if there were an inwardly tapered base to assistin such restraint. Proportionately smaller batch loads may be used,therefore, since the recirculation of the particles is substantiallycontinuous with the particles spending very little time in the annularbed. For this reason, an embodiment of this character is suitable forspecial purposes, while the embodiments of FIG. 1 and FIG. 2 are deemedto be of more general use.

In FIG. 4, this embodiment represents one manner of unloading a coatingapparatus, and was briefly mentioned above with respect to one possibleoperation of the embodiment of FIG. 1.

Only the upper portion of a coating apparatus 60 is shown, and it couldbe used for any of the previously described embodiments. A conduit 62 isinstalled within the upper portion of the apparatus, as shown, and a gasor air porous collection bag 64 may be installed at the remote end ofthe conduit for collecting the finally coated particles in the manneralready heretofore described.

In any of the embodiments described above, the truncated hollow conesmay be adapted to be adjusted for movement upwardly or downwardly in avertical plane. The same may also be accomplished with the aerodynamicstructure, the annular airfoils and the spray nozzles, as desired tosuit gas or air flows, particle sizes and weights, coating materialconsistencies and whatever other controlling factors may be concerned.

The particles or pellets to be coated may be batch-loaded and treated;or, if deemed advantageous, two or more such coating apparatus may bearranged in cascaded manner to provide for a continuous coatingoperation. The inlet for the particles in a cascaded arrangement may bedisposed above the annular storage of one apparatus and the particlesmetered in predetermined manner into the annular storage bed, while theoutlet to the next coating apparatus may be disposed on the oppositeside of the annular storage bed and constitute a weir for outflow ofexcess coated particles. The inlet may also be disposed for gravity flowof particles to or into the annular storage bed. It may be desirable toprovide for different coatings in different apparatus, or providesupplemental coatings.

Multiple spray nozzles may also be employed, as desired, to achievedifferent coating effects.

The examples which follow are submitted for a better understanding ofthe invention. While the examples are based on in vitro tests, the invitro experiments shown in the examples simulate conditions existing inruminants thereby permitting the study of coated pellets without the useof live animals. It has been determined by actual in vivo tests that thetesting of pellets in the aqueous media used in the examples, simulatingthe environmental conditions of the rumen and abomasum with respect totemperature, pH, etc., provide reliable data concerning the protectionoffered by the coatings in the rumen, and releasability of the coatingsin the abomasum. Nutrients such as amino acids and proteins which may beused in the core material are known to be beneficial to ruminants whenpositioned in the intestinal tract downstream from the rumen.

The following examples are submitted for a better understanding of theinvention. Generally, pellets are prepared from the nutrients indicatedto a size of between about 8 and 12 sieve size. The nutrients are mixedwith conventional additives such as microcrystalline cellulose, binders,inert consistency adjusting substances such as water, etc. The pelletsare formed by a conventional pelletizer, dried, sieved, and coated usinga coater as described herein. Upon formation of an imperforate coatingon the pellets, they are tested for resistance to pH conditionsresembling those of the rumen and abomasum by agitating in buffersolutions of pH 2.9 for 0.5 hours and 5.4 for 24 hours. Recovery andprotection figures cited for active core ingredients herein contain inthem all materials of the original coated pellet that are not completelydissolved in the pH 2.9 buffer, including any undissolved activeingredient in the original core. For the sake of simplicity,abbreviations are used in the examples as follows:

2M5VP--2-methyl-5-vinylpyridine

AN--acrylonitrile

Where coating ratios are used, the first number indicates the number ofparts polymer, the second number indicates the number of partshydrophobic substance, and the third number indicates the number ofparts inert flake material. Unless otherwise specified, a coating ratioof 70/30/10, wherein the flake material is aluminum or graphite, isused, and 25% of the hydrochloride of the lycine.HCl is neutralizedusing calcium carbonate. Dimer Acid 1010 is a trademark for dimer acidmarketed by Emery Industries.

Table I compares results obtained using actual abomasal and duodenalfluid extracted from a ruminant with artificial test fluid. In thistable, the polymeric material used is an 80/20 copolymer of2-methyl-5-vinylpyridine and styrene (I.V.=1.23). The core material is90.9% methionine, 3.6% sodium carboxymethyl cellulose and 5.5% sucrose.The pellets are made by first dry mixing 500 g. of methionine, 20 g.sucrose and 10 g. sodium carboxymethyl cellulose. Water (135 g.) isadded and mixed to obtain an extrudable wet powder. The mixture isextruded and chopped to obtain pellets to pass 8 mesh screen and remainon 12 mesh. Ten grams sucrose and 10 g. sodium carboxymethyl celluloseare dry mixed, and added to the wet pellets. The pellets are thentumbled to obtain a uniform coating. Tumbling is continued in hot air toobtain dry pellets.

The coatings are made using the ingredients indicated dissolved orsuspended in acetone at 5% solids level. An air suspension coater isused to coat the pellets.

In the examples, the coating comprises 31.5% polymer, 3.5% stearic acid,and aluminum flake and talc as indicated. Ten percent coating, based onthe weight of the core, is used unless otherwise indicated. pH of theabomasum simulated fluid is 2.9. pH of the rumen simulated fluid is 5.4.Release is measured after one hour periods.

                                      TABLE I                                     __________________________________________________________________________                     pH, Actual                                                                           pH, Actual                                                                          % Release                                                                           % Release                                                                           % Release                                                                             % Release                                                                           % Protection          Example                                                                             Aluminum                                                                             Talc,                                                                             Abomasum                                                                             Duodenum                                                                            Abomasum                                                                            Duodenum                                                                            Abomasum plus                                                                         Abomasum                                                                            Rumen Test            No.   Flake, %                                                                             %   Fluid  Fluid Fluid Fluid Duodenal Fluid                                                                        Test Fluid                                                                          Fluid                 __________________________________________________________________________    1     0      65  2.8    2.9   32    34    66      75    69                    2     5      60  2.8    2.9   26    43    69      --    72                    3     10     55  2.8    2.9   28    40    68      77    84                    4     15     50  2.8    3.0   29    37    78      74    86                    5     25     40  2.8    3.0   28    --    73      73    89                    6     30     35  2.8    3.0   29    46    76      71    92Z                   __________________________________________________________________________

                                      TABLE II                                    __________________________________________________________________________    Effects of Humidity and Temperature on Abomasal Release of Rumen              Protected Glucose After 7 Days Storage                                                                   Percent Recovered From pH 2.9 Buffer                                          0%        80%      100%     Stored                                            Relative Humidity                                                                       Relative Humidity                                                                      Relative Humidity                                                                      Over Water             Example                                                                             Coating Composition                                                                          Original                                                                            25° C.                                                                       60° C.                                                                     60° C.                                                                          25° C.                                                                      60° C.                                                                     25°                                                                        60°         __________________________________________________________________________                                                               C.                 7     70 parts 60/40 2M5VP/AN                                                                      23.2  27.9  30.3         27.2 30.4                                                                              26.2                         30 parts Dimer Acid 1010                                                      30 parts talc-stearic acid                                              8     70 parts 60/40 2M5VP/AN                                                                      25.4  26.4  29.6         28.4 30.8                                                                              28.4                         30 parts Dimer Acid 1010                                                      30 parts talc-oleic acid                                                9     70 parts 60/40 2M5VP/AN                                                                      7.9   8.3   7.8 8.0      7.6  7.9 7.1 9.7                      30 parts Dimer Acid 1010                                                10    70 parts 60/40 2M5VP/AN                                                                      10.1  9.7   11.3                                                                              10.8     9.3  10.7                                                                              9.6 8.4                      30 parts Dimer Acid 1010                                                      10 parts Al                                                             __________________________________________________________________________

                                      TABLE III                                   __________________________________________________________________________    Effects of Humidity and Temperature on Coated Glucose After 7 Day             Storage                                                                                            Percent Recovered From pH 5.4 Buffer                                                0%        80%      100%     Stored                                            Relative Humidity                                                                       Relative Humidity                                                                      Relative Humidity                                                                      Over Water             Example                                                                             Coating Composition                                                                          Original                                                                            25° C.                                                                       60° C.                                                                     60° C.                                                                            25° C.                                                                    60° C.                                                                     25°                                                                        60°         __________________________________________________________________________                                                               C.                 11    70 parts 60/40 2M5VP/AN                                                                      91.3  91.3  96.4         86.4 91.7                                                                              87.9                         30 parts Dimer Acid 1010                                                      30 parts talc-stearic acid                                              12    70 parts 60/40 2M5VP/AN                                                                      90.2  89.6  95.0         89.4 93.1                                                                              86.7                         30 parts Dimer Acid 1010                                                      30 parts talc-oleic acid                                                13    70 parts 60/40 2M5VP/AN                                                                      93.3  93.1  93.6                                                                              93.1     90.6 94.1                                                                              85.6                                                                              23.6                     30 parts Dimer Acid 1010                                                14    70 parts 60/40 2M5VP/AN                                                                      93.1  92.8  97.0                                                                              95.0     90.1 96.0                                                                              88.2                                                                              27,5                     30 parts Dimer Acid 1010                                                      10 parts A1                                                             __________________________________________________________________________

                                      TABLE IV                                    __________________________________________________________________________    Effect of Mechanical Tumbling in a Heated Drum on the Coated Glucose          (Drum Temperature = 80° C.)                                                               Percent Recovered                                                                       Percent Recovered                                                   From pH 5,4 Buffer                                                                      From pH 2.9 Buffer                                                  Heatine Time, hrs.                                                                      Heating Time, hrs.                               Example                                                                            Coating Composition                                                                         0   1  2  0    2                                           __________________________________________________________________________    15   70 parts 60/40 2M5VP/AN                                                                     91.3                                                                              93.3                                                                             95.0                                                                             23.2 23.8                                             30 parts Dimer Acid 1010                                                      30 parts talc-stearic acid                                               16   70 parts 60/40 2M5VP/AN                                                                     90.2                                                                              93.6                                                                             95.9                                                                             25.4 29.5                                             30 parts Dimer Acid 1010                                                      30 parts talc-oleic acid                                                 17   70 parts 60.40 2M5VP/AN                                                                     93.3                                                                              95.7                                                                             96.9                                                                             7.9  7.6                                              30 parts Dimer Acid 1010                                                 18   70 parts 60/40 2M5VP/AN                                                                     93.1                                                                              96.0                                                                             96.0                                                                             10.1 10.0                                             30 parts Dimer Acid 1010                                                      10 parts Al                                                              __________________________________________________________________________

                  TABLE V                                                         ______________________________________                                        Recovery of Coated Glucose Pellets                                            (coating components: 70 parts                                                 60/40 2M5VP/AN, 30 parts Emphol 1010                                          and 30 parts talc-fatty acid mixture)                                                         %      % Recovered From                                       Example                                                                              Talc:Fatty Acid Ratio                                                                        coating  pH 2.9                                                                              pH 5.4                                   ______________________________________                                        19     300:10 stearic 21.5     26.8  90.3                                     20     300:50 stearic 18.6     26.1  81.7                                     21     300:10 oleic   20.5     25.7  90.9                                     22     300:50 oleic   19.9     30.7  74.4                                     ______________________________________                                    

                  TABLE VI                                                        ______________________________________                                        Glucose Pellet Protection with Varying Amounts of                             60/40 2M5VP/AN, Dimer Acid 1010 and Aluminum Flake                                   Coating %         % Recovered From                                     Example  Ratio     Coating   pH 2.9  pH 5.4                                   ______________________________________                                        23       70/30/10  16.2      12.2    92.3                                     24       70/20/10  18.1      10.7    93.6                                     25       70/10/10  16.6      10.4    84.0                                     26       70/30/5   20.0      10.4    72.9                                     ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                        Glucose Pellet Protection with Varying Amounts of                             60/40 2M5VP/AN, Dimer Acid 1010 and Talc-Oleic Acid Mixture                          Coating %         % Recovered From                                     Example  Ratio     Coating   pH 2.9  pH 5.4                                   ______________________________________                                        27       70/30/30  19.4      25.2    94.6                                     28       70/20/30  18.1      24.1    89.6                                     29       70/30/20  15.3      22.4    94.2                                     30       70/20/20  19.1      16.8    95.4                                     31       70/26/10  19.9      14.1    92.9                                     32       70/20/10  18.6      22.3    92.8                                     33       70/10/20  19.7      17.2    95.4                                     34       70/10/10  19.2      18.8    82.4                                     ______________________________________                                    

The fluid used to simulate environmental conditions of the rumen (at pH5.5) is prepared by making 11.397 grams of sodium acetate with 1.322grams of acetic acid and diluting this mixture with demineralized waterto 1 liter.

The fluid used to simulate environmental conditions of the abomasum (atpH 2.9) is prepared by mixing 7.505 grams glycine with 5.85 grams sodiumchloride and diluting this mixture with demineralized water to 1 liter.Eight parts of this solution are mixed with 2 parts of 0.1 normalhydrochloric acid for the test fluid.

The fluids are found to give reliable results in testing the pellets,according to similar experiments using actual rumen and abomasum fluidwithdrawn from a ruminant.

Unless otherwise specified, all ratios, percentages, etc., are byweight, and the ratio of flake material to reactive acid in the examplesis 300:30.

To be useful and practical as a feed for ruminants, it is consideredthat at least 60% and preferably at least 75% of the active ingredientsof the core of the pellets to which this invention relates should bestable in the rumen and release in the abomasum.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

I claim:
 1. A pellet adapted for oral administration to a ruminantcomprising a core material having a pH greater than about 5.68, saidcore material being beneficial to the ruminant postruminally, and acoating surrounding said core material which protects the core materialin the rumen and releases it in the abomasum, said coating comprising(a)a film-forming polymeric material containing at least one basic aminogroup in which the nitrogen content is from 3 to 14% by weight of thetotal molecular weight of the polymeric material, said polymericmaterial comprising cellulose propionate morpholinobutyrate, or at leastone polymer, copolymer or blend of polymers derived from monomersselected from 2-vinylpyridine, 4-vinylpyridine,2-methyl-5-vinylpyridine, and 2-ethyl-5-vinylpyridine, (b) from about 2to about 40% based on the weight of said polymeric material, of ahydrophobic material dispersed in said polymeric material selected fromfatty acids having from 12 to 32 carbon atoms, aluminum salts of fattyacids having from 12 to 32 carbon atoms, or polycarboxylic acids havinga ratio of from 10 to 22 carbon atoms per carboxyl group and a molecularweight of from 400 to 1000, (c) from about 10 to about 200%, based onthe weight of said polymeric material, of a physiologically acceptableflake material dispersed in said polymeric material, and (d) from about5 to about 40% by weight based on the weight of said polymer, of areactive fatty acid,said coating making up about 5 to about 50% of theweight of said pellet, and having a sticking temperature of at leastabout 50° C.
 2. A pellet according to claim 1 wherein said reactive acidis selected from the group consisting of dimer acid, oleic acid, stearicacid, and palmitic acid.
 3. A pellet according to claim 1 wherein saidcore material is selected from the group consisting of glucose,bacitracin, thyrotropin releasing factor and inositol.
 4. A pelletaccording to claim 1 wherein said polymeric material is a copolymer of2-methyl-5-vinylpyridine and styrene.
 5. A pellet according to claim 3wherein said polymeric material is a copolymer consisting essentially ofabout 80% 2-methyl-5-vinylpyridine and about 20% styrene.
 6. A pelletaccording to claim 1 wherein said hydrophobic material is aluminumoleate.
 7. A pellet according to claim 1 wherein said hydrophobicmaterial is stearic acid.
 8. A pellet according to claim 1 wherein saidhydrophobic material is dimer acid.
 9. A pellet according to claim 1wherein said flake material is selected from the group consisting ofmetal flake, mineral flake, and crosslinked organic polymer.
 10. Apellet according to claim 9 wherein said flake material is selected fromthe group consisting of aluminum flake, talc, graphite, and ground mica.11. A composition adapted for use in coating pellets orallyadministrable to a ruminant which protects the core material in therumen and releases it in the abomasum comprising(a) a film-formingpolymeric material containing at least one basic amino group in whichthe nitrogen content is from 3 to 14% by weight of the total molecularweight of the polymeric material, said polymeric material comprisingcellulose propionate morpholinobutyrate, or a polymer, copolymer orblend of polymers derived at least in part from monomers selected from2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and2-ethyl-5-vinylpyridine, and (b) from about 2 to about 40%, based on theweight of said polymeric material, of a hydrophobic material dispersedin said polymeric material selected from fatty acids having from 12 to32 carbon atoms, aluminum salts of fatty acids having from 12 to 32carbon atoms, or polycarboxylic acids having a ratio of from 10 to 22carbon atoms per carboxyl group and a molecular weight of from 400 to1000, and (c) from about 10 to about 200%, based on the weight of saidpolymeric material, of a physiologically acceptable flake materialdispersed in said polymeric material, and (d) from about 5 to about 40%by weight, based on the weight of said polymer, of a reactive fattyacid,said coating having a sticking temperature of at least about 50° C.12. A composition according to claim 11 wherein said polymeric materialis a copolymer of 2-methyl-5-vinylpyridine and styrene.
 13. Acomposition according to claim 11 wherein said polymeric material is acopolymer consisting essentially of about 80% 2-methyl-5-vinylpyridineand about 20% styrene.
 14. A composition according to claim 11 whereinsaid hydrophobic material is aluminum oleate.
 15. A compositionaccording to claim 11 wherein said hydrophobic material is stearic acid.16. A composition according to claim 11 wherein said hydrophobicmaterial is dimer acid.
 17. A composition according to claim 11 whereinsaid flake material is selected from the group consisting of metalflake, mineral flake, and crosslinked organic polymer.
 18. A compositionaccording to claim 17 wherein said flake material is selected from thegroup consisting of aluminum flake, talc, graphite, and ground mica. 19.A pellet adapted for oral administration to a ruminant comprising a corematerial having a pH greater than about 5.68, said core material beingbeneficial to the ruminant postruminally, and a coating surrounding saidcore material which protects the core material in the rumen and releasesit in the abomasum, said coating comprising(a) a film-forming copolymerof about 80% 2-methyl-5-vinylpyridine and about 20% styrene by weight,(b) from about 2 to about 40% based on the weight of said polymericmaterial, of a hydrophobic material dispersed in said polymeric materialselected from aluminum oleate, dimer acid, stearic acid or oleic acid,(c) from about 10 to about 200%, based on the weight of said polymericmaterial, of at least one physiologically acceptable flake materialdispersed in said polymeric material selected from the group consistingof talc, aluminum flake and graphite, and (d) from about 5 to about 40%by weight, based on the weight of said polymer, of a reactive fattyacid,said coating making up about 5 to about 50% by weight of saidpellet, and having a sticking temperature of at least about 50° C.